[FFmpeg-devel] [PATCH] split-radix FFT
Tue Jul 29 20:02:14 CEST 2008
On Tue, Jul 29, 2008 at 07:14:02PM +0300, Uoti Urpala wrote:
> On Tue, 2008-07-29 at 17:32 +0200, Michael Niedermayer wrote:
> > > > > > Though i was more thinking of distributions
> > > > > > that have a policy that says -fPIC must be added to the flags.
> > > > > >
> > > > > > http://www.debian.org/doc/debian-policy/ch-files.html:
> > > > > > 10.2 Libraries
> > > > >
> > > > > Currently FFmpeg in Debian is built without -fPIC on x86.
> > > >
> > > > Iam happy to hear this, still the point stands, distributions have such
> > > > requirements. And it takes the package maintainer quite a bit of work (or
> > > > rulebreaking) to not compile with -fpic.
> > >
> > > And how does using MANGLE improve things?
> > It makes the code run faster and makes it smaller, but i said that already.
> As would just omitting -fPIC, without the ugliness of MANGLE.
First this is not always possible (x86-64 and distro policies)
Second the ugliness is actually debateable
"mov "MANGLE(cos_pi)", %%eax"
is actually more readable than
"mov %7, %%eax"
because cos_pi makes sense and %7 requires one to check what it is actually.
> But my
> question was about the distribution case. I'll rephrase it if if the
> original wasn't clear enough:
> You said that MANGLE helps with distributions that have a policy that
> requires using -fPIC. How does it actually help?
You misunderstood my intention, what i meant was MANGLE helps the users
of the binary package of distributions as the application (ffmpeg) is faster.
Which is an advantage for the user.
> It just creates
> textrels with a different (and uglier) method. Is the benefit that it's
> easier to break the policy without anyone noticing (there's a -fPIC on
> the command line... it's just using another method to negate it). Or do
> you think that someone will count the textrels and say "well breaking
> the policy by this amount of textrels from the asm is ok, even though a
> larger number from the C parts wouldn't be"?
Which policy of which distribution forbids textrels? debians says -fPIC must
be there thats not the same thing.
It was you IIRC who equated -fPIC with no textrels in one of our previous
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
While the State exists there can be no freedom; when there is freedom there
will be no State. -- Vladimir Lenin
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